Minimally invasive medical techniques are aimed at reducing the amount of extraneous tissue which is damaged during diagnostic or surgical procedures, thereby reducing patient recovery time, discomfort, and deleterious side effects. Millions of surgeries are performed each year in the United States. Many of these surgeries can potentially be performed in a minimally invasive manner. However, only a relatively small number of surgeries currently use these techniques due to limitations in minimally invasive surgical instruments and techniques and the additional surgical training required to master them.
Advances in minimally invasive surgical technology could dramatically increase the number of surgeries performed in a minimally invasive manner. The average length of a hospital stay for a standard surgery is significantly larger than the average length for the equivalent surgery performed in a minimally invasive surgical manner. Thus, the complete adoption of minimally invasive techniques could save millions of hospital days, and consequently millions of dollars annually in hospital residency costs alone. Patient recovery times, patient discomfort, surgical side effects, and time away from work are also reduced with minimally invasive surgery.
The most common form of minimally invasive surgery may be endoscopy. Probably the most common form of endoscopy is laparoscopy, which is minimally invasive inspection and surgery inside the abdominal cavity. In standard laparoscopic surgery, a patient""s abdomen is insufflated with gas, and cannula sleeves are passed through small (approximately xc2xd inch) incisions to provide entry ports for laparoscopic surgical instruments.
The laparoscopic surgical instruments generally include a laparoscope for viewing the surgical field, and working tools defining end effectors. Typical surgical end effectors include clamps, graspers, scissors, staplers, or needle holders, for example. The working tools are similar to those used in conventional (open) surgery, except that the working end or end effector of each tool is separated from its handle by, e.g., an approximately 12-inch long, extension tube.
To perform surgical procedures, the surgeon passes these working tools or instruments through the cannula sleeves to a required internal surgical site and manipulates them from outside the abdomen by sliding them in and out through the cannula sleeves, rotating them in the cannula sleeves, levering (i.e., pivoting) the instruments against the abdominal wall and actuating end effectors on the distal ends of the instruments from outside the abdomen. The instruments pivot around centers defined by the incisions which extend through muscles of the abdominal wall. The surgeon monitors the procedure by means of a television monitor which displays an image of the surgical site via a laparoscopic camera. The laparoscopic camera is also introduced through the abdominal wall and into the surgical site. Similar endoscopic techniques are employed in, e.g., arthroscopy, retroperitoneoscopy, pelviscopy, nephroscopy, cystoscopy, cisternoscopy, sinoscopy, hysteroscopy, urethroscopy and the like.
There are many disadvantages relating to current minimally invasive surgical (MIS) technology. For example, existing MIS instruments deny the surgeon the flexibility of tool placement found in open surgery. Most current laparoscopic tools have rigid shafts and difficulty is experienced in approaching the surgical site through the small incision. Additionally, the length and construction of many surgical instruments reduces the surgeon""s ability to feel forces exerted by tissues and organs on the end effector of the associated tool. The lack of dexterity and sensitivity of surgical tools is a major impediment to the expansion of minimally invasive surgery.
Minimally invasive telesurgical systems for use in surgery are being developed to increase a surgeon""s dexterity as well as to allow a surgeon to operate on a patient from a remote location. Telesurgery is a general term for surgical systems where the surgeon uses some form of remote control, e.g., a servomechanism, or the like, to manipulate surgical instrument movements rather than directly holding and moving the instruments by hand. In such a telesurgery system, the surgeon is provided with an image of the surgical site at the remote location. While viewing typically a three-dimensional image of the surgical site on a suitable viewer or display, the surgeon performs the surgical procedures on the patient by manipulating master control devices, at the remote location, which control the motion of servomechanically operated instruments.
The servomechanism used for telesurgery will often accept input from two master controllers (one for each of the surgeon""s hands), and may include two robotic arms. Operative communication between each master control and an associated arm and instrument assembly is achieved through a control system. The control system includes at least one processor which relays input commands from a master controller to an associated arm and instrument assembly and from the arm and instrument assembly to the associated master controller in the case of, e.g., force feedback.
It would be advantageous if the position of the image capturing device could be changed during the course of a surgical procedure so as to enable the surgeon to view the surgical site from another position. It will be appreciated that, should the image capturing device position change, the orientation and position of the end effectors in the viewed image could also change. It would further be advantageous if the relationship in which end effector movement is mapped onto hand movement could again be established after such an image capturing device positional change.
It is an object of the invention to provide a method and control system for a minimally invasive surgical apparatus which maps end effector movement onto hand movement. It is further an object of the invention to provide a method and control system for a minimally invasive surgical apparatus which permits the mapping of end effector movement onto hand movement to be reestablished after having been interrupted, for example, by an image capturing device positional change.
It is to be appreciated that although the method and control system of the invention is described with reference to a minimally invasive surgical apparatus in this specification, the application of the invention is not to be limited to this application only, but can be used in any type of apparatus where an input is entered at one location and a corresponding movement is required at a remote location and in which it is required, or merely beneficial, to map end effector orientational and positional movement onto hand movement through an associated master control device.
The invention provides enhanced telepresence and telesurgery systems which automatically update coordinate transformations so as to retain coordination between movement of an input device and movement of an end effector as displayed adjacent the input device. The invention generally maps a controller workspace (in which the input device moves) with an end effector workspace (in which the end effector moves), and effects movement of the end effector in response to the movement of the input device. This allows the use of kinematically dissimilar master and slave linkages having, for example, different degrees of freedom. Using an image capture device coupled to the end effector linkage allows calculation of the desired mapping coordinate transformations automatically. Input member pivot to end effector jaw pivot mapping enhances the operator""s control, while the use of intermediate transformations allows portions of the kinematic train to be removed and replaced. Dexterity is enhanced by accurately tracking orientation and/or angles of movement, even if linear movement distances of the end effector do not correspond to those of the input device.
In a first aspect, the invention provides a surgical robotic system comprising a master controller having an input device moveable in a controller workspace. A slave has a surgical end effector and actuator, the actuator moving the end effector in a surgical workspace in response to slave actuator signals. An imaging system includes an image capture device with a field of view moveable in the surgical workspace. The imaging system generates state variable signals indicating the field of view. A processor couples the master controller to the slave arm. The processor generates the slave actuator signals by mapping the input device in the controller workspace with the end effector in the surgical workspace according to a transformation. The processor derives the transformation in response to the state variable signals of the imaging system.
The processor will generally derive the transformation so that an image of the end effector in the display appears substantially connected to the input device in the controller workspace. The processor can determine a position and orientation of the input device in the master controller space from state variable signals generated by the master controller. Similarly, the processor will often determine a position and orientation of the end effector in the surgical workspace from the state variable signals of the slave. The processor can then generate the slave actuator signals by comparing the position and orientation of the input device and the end effector in the mapped space. Advantageously, this end-to-end mapping allows the use of very different kinematic trains for the master and slave systems, greatly facilitating specialized linkages such as those used in minimally invasive surgery.
In many embodiments, the slave and imaging system will be coupled to facilitate derivation of the transformation by the processor from state variable signals provided from these two structures. For example, the imaging system may comprise a linkage moveably supporting the image capture device, and the slave may also comprise a linkage moveably supporting the end effector. The linkages may comprise joints having joint configurations indicated by the state variable signals. The linkages may be coupled in a variety of ways to facilitate derivation of the transformation by the processor. The coupling of the slave and imaging systems may be mechanical, electromagnetic (such as infrared), or the like. In the exemplary embodiment, the slave and imaging system linkages are mounted to a common base. This base may comprise a wheeled cart for transportation, a ceiling or wall mounted structure, an operating table, or the like. The state variable signals from the imaging system and/or slave need not necessarily comprise joint configuration or position signals, as the transformation may instead be derived from magnetic sensors (including those which can direct both location and orientation), image recognition-derived information, or the like. Regardless, the processor will preferably derive the transformation in real time, thereby allowing enhanced dexterity during and after image capture device movement, changes of association between masters and slaves, tool changes, repositioning of either the master or slave relative to the other, or the like.
In another aspect, the invention provides a surgical robotic system comprising a master controller having an input device moveable in a controller workspace. A slave has a surgical end effector and at least one actuator coupled to the end effector. The actuator moves the end effector in a surgical workspace in response to slave actuator signals. An imaging system includes an image capture device with a field, of view moveable in the surgical workspace. The imaging system transmits an image to a display. A processor couples the master controller to the slave arm. The processor generates the slave actuator signals by mapping the input device in the controller workspace with the end effector in the surgical workspace according to a transformation. The processor derives the transformation so that an image of the end effector in the display appears substantially connected to the input device in the workspace.
Often times, the master controller will comprise a linkage supporting the input device, while the slave comprises a linkage supporting the end effector, with the master linkage and the slave linkage being kinematically dissimilar. More specifically, joints of the master linkage and joints of the slave linkage will have different degrees of freedom, and/or the joints will define different locations in the mapped space. End-to-end mapping of the input device and end effector allow the processor to accurately generate the desired slave actuation signals despite these kinematic dissimilarities, which can be quite pronounced in specialized slave mechanisms such as those used in minimally invasive robotic surgery.
In the exemplary embodiment, the processor will derive the transformation indirectly using an intermediate reference frame located at a detachable connection along a linkage supporting the master, end effector, and/or image capture device. This indirect transformation calculation significantly facilitates replacement or modification of a portion of the subsystem.
The substantial connection presented to the system operator between the input device and the end effector can be enhanced by directing non-visual sensory information to the operator corresponding with the image on the display. The non-visual information will preferably indicate force and/or torque applied to the slave. While the information may be presented in a variety of forms, including audio, thermal, smell, or the like, the non-visual information will preferably be in the form of loads, forces, and/or torques applied via the input device to the hand of the operator, ideally with orientations substantially corresponding to the orientations of the forces and torques applied to the slave (according to the image of the slave shown in the display). As described above regarding movement, correlation between orientations and torques on the input device in the slave may be revised by the controller (often when the transformation is revised) using end-to-end mapping. Optionally, the force and torque information presented to the operator indicates contact information (for example, engagement between an end effector and a tissue), disturbance information (for example, where one slave arm engages another slave arm outside a patient body), and/or synthetic information (including limitations on movements or xe2x80x9cvirtual wallsxe2x80x9d calculated in a simulated domain to prevent movement of an end effector in a restricted direction). Hence, the force and torque information may be derived from slave motor signals, sensors (including force sensors, pressure sensors, acceleration sensors, velocity sensors, or the like), simulation (including computed constraints), and other sources.
In another aspect, the invention provides a surgical robotic system comprising a master controller having an input device supported by a linkage so that the input device can move in a controller workspace with a first number of degrees of freedom. A slave has a surgical end effector and a plurality of actuators coupled thereto so that the end effector can move in a surgical workspace with a second number of degrees of freedom in response to slave actuator signals, the second number being less than the first number. A processor couples the master controller to the slave. The processor generates the slave actuator signals by mapping the input device in the controller workspace with the end effector in the surgical workspace. This allows, for example, the use of masters having at least one redundant degree of freedom, or the use of a full six degree of freedom master with a slave having a more limited motion capability. Such masters can give a wide range of motion to a surgeon without constraining slave design, size, complexity, and/or end effector interchangeability.
In yet another aspect, the invention provides a surgical robotic system comprising a master controller having an input device moveable in a controller workspace. A slave comprises a slave arm and a first tool releasably mountable on the arm. The first tool has a first end effector which moves in a surgical workspace in response to slave actuator signals. A second tool is releasably mounted on the slave in place of the first tool. The second tool has a second end effector moveable in the surgical workspace in response to the slave actuator signals. The second tool is kinematically dissimilar to the first tool. The processor couples the master controller to the slave arm. The processor generates the slave actuator signals by mapping the input device in the controller workspace with the end effector of the mounted tool in the surgical workspace.
In a still further aspect, the invention provides a surgical robotic system with a master controller moveable in a master controller space. The input device has a grip sensor for squeezing with a hand of an operator. The grip sensor defines a grip pivot. The slave arm has an end effector supported by a linkage so that the end effector is moveable in an end effector workspace. The slave arm has actuators coupled to the linkage for moving the end effector in response to slave actuator signals. The end effector comprises jaws with a jaw pivot. An image capture device has a field of view within the end effector workspace and transmits an image to a display. A processor couples the master controller to the slave arm, the processor generating the slave actuator signals in response to movement of the input device so that the jaw pivot in the display appears substantially connected with the grip pivot.
A still further aspect of the present invention provides a surgical robotic system comprising a master controller having an input device moveable with a plurality of degrees of freedom in a master controller space. The movement of the input device defines at least one angle selected from the group comprising a change in angular orientation and an angle of translation. A slave arm has an end effector supported by a linkage with a plurality of joints so that the slave is moveable in an end effector workspace. The slave arm has actuators coupled to the joints for moving the end effector in response to slave actuator signals. An image capture device transmits an image to a display adjacent to the master controller. A processor couples the master controller to the slave arm. The processor generates the slave actuator signals in response to the movement of the input device so that at least one angle selected from the group comprising a change in angular orientation and an angle of translation of the end effector is within five degrees of the at least one angle of the input device. Advantageously, such angular accuracy can enhance the substantial connectedness of the input device and the end effector despite significant differences in movement distances perceived by the system operator.
In a method aspect, the invention provides a surgical robotic method comprising moving a master input device in a controller workspace by articulating a plurality of master joints. A surgical end effector is moved in a surgical workspace by articulating a plurality of slave joints in response to slave motor signals. An image of an arbitrary field of view within the surgical workspace is displayed on a display adjacent the master controller. The slave motor signals are automatically generated in response to moving the master so that an image of the end effector in the display appears substantially connected with the input device in the master controller space.
In yet another system aspect, the invention provides a surgical robotic system comprising a master controller having an input device moveable in a master controller space. The input device includes first and second grip members for actuating with first and second digits of a hand of an operator. A slave has a surgical end effector that moves in a surgical workspace in response to slave actuator signals. The end effector includes first and second end effector elements. A processor couples the master to the slave. The processor generates the slave actuator signals so that movement of the first grip member substantially maps movement of the first end effector element, and so that movement of the second end effector element substantially maps movement of the second end effector element.
The grip members and end effector elements shown in the display may optionally be substantially connected at the pivotal joints between the grip members and end effector elements. Alternatively, the point of substantial connectedness may be disposed at midpoints between the tips of the grip members and end effector elements, particularly when using tools having relatively long end effector element lengths between the pivot point and the tip.
In yet another aspect, the invention provides a surgical robotic system comprising a master controller having a surgical handle supported by a plurality of joints so that the handle is moveable in a master controller space. The joints define a gimbal point of rotation about a plurality of axes, and the handle is adjacent the gimbal point. A slave has a surgical end effector which moves in a surgical workspace in response to movement of the handle. This can reduce the inertia of the master system when the surgeon changes orientation, particularly when the handle is substantially coincident with the gimbal point. Often times, a processor couples the master to the slave, and generates slave actuator signals so that the gimbal point of the master is substantially connected to a last joint of the slave adjacent the end effector.
In yet another system aspect, the invention provides a surgical robotic system comprising a master controller having a handle which moves in a master controller workspace. A slave supports a surgical end effector and moves the end effector within a surgical workspace in response to slave actuation signals. A processor couples the master to the slave. The processor generates the slave actuation signals so that movement of a mapping point along the handle of the master controller substantially maps movement of a mapping point along the end effector. The processor is capable of changing at least one of the handle mapping point and the end effector mapping point.
In general, the actuators may comprise a variety of motors (including electric, hydraulic, pneumatic, and the like). In other embodiments, the actuators may comprise brakes, clutches, vibrating devices which apply cycling loads using inertia, or the like. Still other actuators may used, particularly those which provide tactile stimulation in the form of heat, or the like. The tools of the present invention may include a variety of surgical tools and/or end effectors including forceps, grips, clamps, scissors, electrosurgical and mechanical scalpels, and the like. Still further end effectors may provide irrigation, aspiration or suction, air jets, lights, and/or imaging devices. General robotic systems are also provided (analogous to those described above), and both general and surgical robotic methods.
While these systems, methods, and devices are particularly advantageous for robotic surgery, the present invention also encompasses similar robotic systems, methods, and devices for telemanipulation and telepresence in other fields and for general robotic applications.